How to make sense of your Samsung firmware number
Every time a new firmware update appears there's a build number attached to it that may seem like total gobbledegook to you. You've probably noticed that your model number appears in there but the rest is likely a mystery. Not anymore! We'll explain how the Samsung firmware build numbering system works, so you can tell what you're looking at.
It's all pretty simple really, once you know what you're looking for. It's basically broken up into three parts, which are kind of obvious if you think about: device model, country/language, build date information. This is why when flashing firmware manually through Odin you need to make sure you have the right firmware for your region and model. Knowing the date that firmware was compiled also helps you know what is newer and identify the problematic firmware builds when things go astray.
So, let's get to it. The latest firmware available for the Galaxy S4 international variant is I9500XXUFNC1. Obviously, the I9500 is the model number for the international Galaxy S4. The next few letters are country code/CSC (customer software customization) related, you can find CSC code references on XDA and other sites, but you only need to look it up once for your country/CSC. The letter F in the example above (just before the last three numbers/letters) relates to the original Android version the firmware was based on, in this case Android 4.4.2.
Finally, we get to NC1 - the business end - which is the date information and the stuff you want to keep an eye on the most when new builds appear. Years are covered alphabetically by the first character, where N is 2014, then the next letter is the month of the year, making this build from March. The final character is the revision code or version number within that month, so this firmware is the first version from March, 2014. If the versions in a month go beyond nine, the final character will become a letter, so A will be 10, B will be 11 and so on.
Here are the date codes for your reference::
J = 2010
K = 2011
L = 2012
M = 2013
N = 2014
and so on...
A = January
B = February
C = March
D = April
E = May
F = June
G = July
H = August
I = September
J = October
K = November
L = December
other letters will likelty refer to test builds, pre-release builds etc.
Which part of the firmware number did you already know? Any other Android numbering you'd like to know about?
Wait a sec, in the screens there is something wrong. As far as I know, Samsung ditched the green batteries with KK, so why they are still there?
Looking at the date in the screenshots, I'll assume this was incomplete test firmware. I recognize the copyright holders name from XDA Developers too. But you're right, in the official firmware the icons are white! Good eyes @Philipp!